Endodontically treated teeth are susceptible to fracture, and their restoration often poses a challenge to the restorative dentist. This susceptibility to fracture has been generally ascribed to increased brittleness and to the loss of tooth structure resulting from caries, endodontic access preparation and instrumentation. Limitations of testing techniques, generally involving loading to fracture, have hampered the systematic assessment of the contributions of the various steps in endodontic and restorative procedures, to overall loss of tooth strength. Strain gauge technology, in association with closed-loop servohydraulics, offers considerable advantages in the non- destructive measurement of loss of strength at each stage of endodontic and restorative treatment of teeth. Strain gauges bounded to enamel measure the flexure of the tooth under lad, and the closed-loop servohydraulic system permits controlled loading of the tooth under conditions of static load or simulated functional and parafunctional movements. Because the tooth is not stressed to the point of fracture, multiple measurements can be made on each tooth; the loss of stiffness associated with each step in the endodontic and restorative procedures and the regaining of stiffness with placement of an appropriate restoration, can be measured with each tooth serving as its own control. This pilot study is planned to investigate the feasibility of using multiple strain gauges on single extracted teeth, to measure the effects of endodontic and restorative procedures on loss of tooth strength. Placement of gauges on buccal, lingual and proximal surfaces will allow the simultaneous measurement of flexure in different locations, in response to static loading and to chewing and bruxing cycles. The extent and the nature of the strains (either tension or compression) in different locations, and their potential contribution to fracture susceptibility will permit a more rational approach to design of cavity preparations and restoration of endodontically treated teeth. This approach has potential application to many aspects of the restoration of endodontically treated teeth, including the design and placement of posts and pins, and the use of dentin-bonded restorative materials.